The decision to allow families to have two children was designed "to improve the balanced development of population'' and to deal with an aging population, according to the statement from the Community Party's Central Committee carried by the official Xinhua News Agency (in Chinese) on Thursday.

Currently about 30% of China's population is over the age of 50.

Correspondents say that despite the relaxation of the rules, many couples may opt to only have one child, as one-child families have become the social norm.